Linear alpha-olefins, which are important materials used as comonomers, cleaners, lubricants, plasticizers and the like, are commercially widely used, and particularly, 1-hexene and 1-octene are used a lot as comonomers for controlling the density of polyethylene when preparing linear low-density polyethylene (LLDPE).
In the preparation process of common LLDPE, copolymerization of alpha-olefins, for example, 1-hexene, 1-octene, etc. with ethylene is performed to control density by forming branches on the polymer backbone.
Accordingly, in the preparation of LLDPE having a high comonomer content, the comonomer is a costly part. To resolve the drawback, various methods have been conducted.
In addition, the application field or the market size of alpha-olefins is dependent on the kind thereof, and technique on selective production of a specific olefin is commercially very important. Recently, research on chromium catalysts for preparing 1-hexene or 1-octene with high selectivity via selective ethylene oligomerization has been actively conducted.
Conventional commercial preparation methods of 1-hexene or 1-octene include the shell higher olefin process (SHOP) of Shell Chemicals, the Ziegler process of Chevron Philips chemical, etc. Through the methods, alpha-olefins having a wide distribution of C4-C20 may be obtained.
Meanwhile, research on the deactivation technique of an oligomerization catalyst system used during preparing has been continuously conducted. If the oligomerization catalyst is not deactivated, alpha-olefins produced may be isomerized during the subsequent separation process. Therefore, a deactivator for deteriorating or removing the activity of the oligomerization catalyst system is required.
Conventionally, long chain alcohols for example, decanol, etc. were used so as not to inhibit the separation of an alpha-olefin product, however the materials might become a contaminating material in a product, and a separating process of the decanol was essential.
Accordingly, a deactivating technique of an oligomerization catalyst system which may effectively prevent a side reaction during the separating process of the alpha-olefins thus produced and decrease costs and equipments required for the separation of a deactivator, is required.